This dissertation uses the large shock to the British cotton textile industry in the 19th century, caused by the U.S. Civil War (1861-1865), in order to address three long-running questions about technological progress and industry development. The cotton textile industry was a large and important sector in the British economy during the 19th century. The industry was entirely dependent on imported raw cotton, most of which came from the U.S. South prior to the Civil War. The onset of the war sharply reduced the supply of Southern cotton to the British market, causing a severe downturn in the industry. In response to the shock, cotton textile producers turned to other sources of supply, chiefly India, but also Egypt, Brazil and others, to h...